At this point, I am inclined to think Susan Rice will be Biden’s running mate. The plan of the dominant factions of the ruling class seems to be to get rid of Trump, whom they regard as a loose cannon with “dangerous” isolationist instincts, elect Biden and then cart Sleepy Joe the Pedo off to a nursing home, with the Veep acting a the de facto Prez. Susan Rice would be their ideal pick, a technocratic State Department insider with experience in empire management within a liberal internationalist but hawkish framework.
The power elite seems to (correctly) regard Kamala Harris as a sleazy gold-digger and opportunist who is untrustworthy in addition to her lack of foreign policy experience. The other potential picks are too inexperienced, too inflammatory from a “culture war” perspective (the neocons and Never Trump Repugs are an influential part of the Biden coalition) or, in the case of Lizzie the Scamster, too rhetorically threatening from an economics perspective.
If the Democraps do not choose Rice, it will probably be because they don’t think she is sellable to the “progressive” wing fo their party. The main thing the Democratic strategists are worried about is low voter turnout (particularly given the pandemic). They probably know they fucked up in 2016 by taking their “left” voters for granted and focusing exclusively on swing voters and anti-Trump Republicans. This time they probably want to make sure they have both their left and right flanks covered.